1. Field of the Invention
The present invention relates to an optical functional module on which is mounted an optical functional device such as an attenuator device, a shutter device, or a switching device for attenuating or interrupting an optical signal used in optical communication or the like, or for switching between paths for optical signals.
2. Description of the Related Art
In an optical network using optical fibers and used for the Internet or the like, there is a need to perform attenuation or interruption of optical signals, switching of signal paths, etc., in a repeater. Various optical functional components such as attenuators, shutter devices and switching devices having corresponding functions are therefore used.
Enlargement of a relay station becomes a problem due to the increase of a necessary number of relay devices in accordance with the recent increase in traffic of information communication such as optical communication.
Therefore, there is a demand that these optical functional parts be miniaturized into a module to thereby miniaturize the relaying equipment.
These modularized optical functional parts and compact optical function modules composed of collimator blocks provided with collimators sending/receiving optical signals as parallel light beam flux have been used in the relay station for the optical communication network or the like.
FIGS. 7A and 7B show a conventional example of an optical function module. FIG. 7A is a plan view of the conventional optical function module 200. FIG. 7B is a front view of the conventional optical function module 200 shown in FIG. 7A.
The conventional optical function module 200 is composed of collimators 101 and 101xe2x80x2 and a collimator support member 203 holding and facing the collimators 101 and 101xe2x80x2 disposed on a substrate 204. The collimators are connected to optical cables 102 and 102xe2x80x2, respectively.
An optical signal passes through the optical cable 102 and is sent from the collimator 101 as a parallel optical beam flux toward the confronting collimator 101xe2x80x2. Thus, a light flux 106 is formed passing through a space between the confronting collimators 101 and 101xe2x80x2.
The optical functional part 124 is disposed directly on the substrate 204 whereby the optical functional part 124 exhibits its function to the light flux 106. Also, three or more collimators are provided on the collimator support member 203 and a switching device is used as the optical functional part 124 to thereby make it possible to perform the switching of paths of optical signals.
The important aspect of this conventional optical function module is the position of the optical functional part on the substrate.
In order to perform the attenuation, interruption and path change of the optical signals, the optical signal that has passed through the optical cable is sent as a parallel light beam flux by the collimator having an integral structure of a fiber and a lens, and the optical functional part is caused to come into contact with this parallel light beam flux to thereby perform the attenuation, interruption and path change of the optical signal.
However, a diameter of the light flux is about 500 xcexcm, for example. In addition, the optical functional part is a very compact part. For this reason, in order to cause the optical functional part to come into exact contact with the light flux and to exhibit its function, even if there is a very slight shift with respect to the light flux in direction and position of the optical functional part, the function of the optical function module is impaired. In order to prevent this shift, whenever the optical functional part is to be mounted on the substrate, it is necessary to perform the mounting operation while measuring the exact position and direction. This causes the increase of the load on manufactures largely in terms of the cost and working efficiency.
Also, the mounting operation of the optical functional part is performed by means of fastening means such as welding, adhesives and screws.
However, for example, in the case of using the welding for mounting, it is very difficult to perform the welding operation under the condition for keeping the optical functional part at the suitable position and level for a long period of time. Also, there is a fear that the substrate would expand or shrink by the heat generated upon the welding operation so that an error would occur in position and direction of the optical functional part. Also, in order to prevent the damage of the optical functional part due to the heat, there is a limit to the area to be welded. Thus, there is a fear that a shift may occur due to the lack of the adhesive strength.
On the other hand, in case of the mounting operation with adhesives, it is possible to resolve the above-described problem of the heat generated by the welding but in order to prevent the occurrence of the error, there is a problem in that the optical functional part is required to be kept in the suitable position and direction for a long period of time until the adhesives completely dries.
Furthermore, in the conventional case, as described above, the optical functional part is mounted directly on the substrate. If any problem supposedly occurs irrespective of the error in the position and direction of the optical functional part and the fault of the function thereof, in the case where the mounting operation is performed by welding or with the adhesives, it is difficult to readjust the position and direction of the optical functional part and exchange of the optical functional parts.
Also, in case of the mounting operation by screws, it is possible to change the optical functional parts. In case of the readjustment, although it is possible to provide a new screw hole in a place far from the existing screw hole, in the readjustment of the very short distance and direction, it is impossible to provide any new screw hole due to the hindrance of the existing screwhole. It is therefore difficult to perform the readjustment.
In view of the above, it is very difficult to reuse each part such as an optical functional part and a substrate in the conventional optical function module. There is a problem in terms of a cost or a maintaining property.
In view of such circumstances, an object of the present invention is to provide an optical function module in which an optical functional part may be rapidly and easily disposed in a position where the function thereof exhibits exactly and the parts are readily replaced and may be reused.
Aspects of the present invention will be described here in after.
A first aspect of the present invention relates to an optical function module, characterized by comprising: a collimator block including a substrate, at least two or more facing collimators disposed on the substrate, and at least two collimator support members for supporting the collimators; and an optical functional part unit including an optical functional part to be disposed on the collimator block and an arrangement means for arranging the optical functional part on the collimator block.
According to a second aspect of the present invention, in the first aspect of the invention, an optical function module is characterized in that the arrangement means comprises a recess portion provided in the substrate and a holder base engaged exactly with the recess portion for arranging the optical functional part in a position where the optical functional part exactly works on a light flux between the collimators.
According to a third aspect of the present invention, in the first or second aspect of the invention, an optical function module is characterized in that the arrangement means comprises at least one guide pin provided on the substrate and a guide pin insertion hole corresponding to the guide pin, and a holder base for engaging the guide pin and the guide pin insertion hole with each other to dispose the optical functional part to a position where the optical functional part exactly works on a light flux between the collimators.
According to a fourth aspect of the present invention, in any one of the first to third aspects of the invention, an optical function module is characterized in that the optical functional part is an optical filter device for obtaining a transmission light having a predetermined wavelength from a light flux between the collimators.
According to a fifth aspect of the present invention, in any one of the first to third aspects of the invention, an optical function module is characterized in that the optical functional part is a shutter device for interrupting a light flux between the collimators.
According to a sixth aspect of the present invention, in any one of the first to third aspects of the invention, an optical function module is characterized in that an optical functional part is an attenuating device for attenuating a light flux between the collimators.
According to a seventh aspect of the present invention, in any one of the first to sixth aspects of the invention, an optical function module is characterized in that the optical functional part is provided with a piezoelectric actuator using as a power source a vibration generated in a piezoelectric vibrating member as a driving source.
According to an eighth aspect of the present invention, in any one of the first to seventh aspects of the invention, an optical function module is characterized in that the substrate, the collimator support member, the holder base and the arrangement means are made of stainless steel.
According to a ninth aspect of the present invention, in any one of the first to eighth aspects of the invention, an optical function module is characterized in that the substrate, the collimator support member, the holder base and the arrangement means are made of super engineering plastics.